Conveyor system with diverting track network

ABSTRACT

A conveyor sorter and method of laterally displacing articles for diverting articles from a conveying surface includes providing a plurality of movable pushers that are associated with the conveying surface and adapted to move transversely across the conveying surface. A plurality of diverting rails are configured to guide selected ones of the movable pushers across the conveying surface. A plurality of diverters are adapted to selectively divert at least one movable pusher to the diverting tracks when activated into a diverting state. The diverting tracks may include segments that are oriented at different angles with respect to the direction of movement of the conveying surface. This causes selected pusher shoes to be laterally displaced at a first rate during an initial portion of the travel and at a second rate during a subsequent portion of the travel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 10/284,591, filedOct. 31, 2002, now U.S. Pat. No. 6,923,308, which claims priority fromU.S. provisional application Ser. No. 60/397,885, filed Jul. 23, 2002,and U.S. provisional application Ser. No. 60/343,708, filed Nov. 1,2001, the disclosures of which are hereby incorporated herein byreference.

BACKGROUND OF THE INVENTION

This invention relates generally to conveyor diverting systems, and moreparticularly to conveyor diverting systems having an endless conveyingsurface composed of multiple surface members, each one or group ofadjacent ones mounted with a laterally movable shoe capable of divertingpackages or other articles from the conveying surface by pushinglaterally against the articles as they move down the conveyor. Suchlateral pushing diverts a package from a main conveyor to an adjacentbranch conveyor, or other receiving structure.

Conveyor diverting systems using a moving conveying surface consistingof a plurality of parallel surface members have been known for a numberof years. Such diverting systems utilize a diverter shoe movably mountedon one or more of the surface members for lateral movement with respectto the conveying surface under the guidance of a track network Such asystem is disclosed, for example, in commonly-assigned U.S. Pat. No.5,127,510 issued to Cotter et al., and commonly-assigned U.S. Pat. No.5,165,515 issued to Nitschke et al., the disclosures of which are herebyincorporated herein by reference. The track network is located generallyunder the conveying surface and guides the diverter shoes via followerportions descending from the diverter shoes and engaging the tracknetwork. Diverters or diverter switches in the track network selectivelytransfer guidance of each diverter shoe from a track running in thedirection of the movement of the conveying surface to a diagonal track,or plurality of diagonal tracks, in order to cause lateral movement ofthe diverter shoes. Examples of diverter switches used to selectivelytransfer guidance of diverter shoes between tracks are disclosed in U.S.Pat. No. 5,409,095, issued to Hoshi et al., and U.S. Pat. No. 5,039,912,issued to Cotter, and International Publication No. WO 01/83342 A1 byBozarth et al. In order to avoid wasted spacing between variable-lengthpackages, such diverting systems may include manual or automaticmeasuring means at an infeed point to cause the diverter gate associatedwith the selected branch conveyor to divert a selected number of shoescorresponding in general to the length of the package. Exemplary of thistype of conveyor are U.S. Pat. No. 3,361,247, issued to James N. Lauzonet al. and U.S. Pat. No. 4,738,347, issued to Brouwer, the latter beingcommonly assigned with the present invention.

The diverters or diverter switches used to divert the shoes ontodiagonal tracks are often desirably spaced apart approximately the samedistance as the distance between adjacent surface members. This spacingallows adjacent diverters to divert shoes along adjacent surfacemembers. Such spacing, however, often leaves little room for thediverter switches. In order to construct diverter switches that canoperate in such spaces, it is often necessary to construct the diverterswitches so that they divert shoes at a relatively steep angle. That is,the diverter switches are constructed so that they change the motion ofthe shoes from a state in which the shoes are traveling longitudinallywith no transverse motion to one in which they have a relatively hightransverse motion component. In general, the steeper the angle at whichthe diverter switches divert shoes in a transverse direction, the morespace that is created for the physical structure of the diverting gateto occupy. Diverting the shoes at too steep of an angle, however, cancause difficulties as will be set forth in more detail below.

With increased demands for the number of packages to be conveyed by suchconveying systems, the overall speed of the conveyor has become animportant factor in the design of conveying systems. As a generalmatter, increasing the speed of the conveyor typically increases thethroughput of the conveyor. Increasing the speed of the conveyor,however, can create other difficulties. For example, if the longitudinalspeed of the conveyor is increased, the lateral speed of the divertershoes will also increase during package diverts. If this lateral speedgets too great, however, the diverter shoes may impinge the package withsuch force that the package is toppled, knocked backwards on theconveyor, knocked off of the conveyor, or otherwise undesirably moved.While the lateral speed of the diverter shoes can be decreased bylessening the angle of the diverting tracks, as noted above, decreasingthe angle of the diverting tracks may not leave sufficient room for thediverter switches to be operably installed. Also, decreasing the divertangle generally requires the adjacent take-away conveyors to take upmore space in order to accommodate the greater effective width of thearticle when it is diverted at a smaller angle. Having larger take-awayconveyors not only increases their expense, but also uses up morefactory floor-space, which is often at a premium. Further, the need cantherefore be seen for a diverting conveyor that mitigates theaforementioned problems associated with increased conveyor speeds.

Increased demands for package throughput also make the amount ofinter-package spacing an important factor. By spacing packages closertogether, more packages can be placed on a conveyor, and thus morepackages can typically be processed over a given time period when theyare spaced more closely together. However, a minimum inter-packagespacing is desirable as a result of the rotation of a diverted packageas it is diverted. Because of this rotation, additional inter-packagespacing is required to avoid conflict between the package being divertedand a closely trailing package. This rotation pushes the trailing cornerof the package adjacent the branch conveyor back a distance. Sufficientspacing between the packages to accommodate the backward movement ofthis corner is desirably included in conveyor systems. The extent ofthis spacing, however, is desirably reduced, and the need can be seenfor a conveyor diverting system that can more effectively decrease theamount of necessary inter-package spacing.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a sortation system whichmitigates a number of the above-discussed difficulties. The sortationsystem is designed to lessen the impact of the diverter shoes againstarticles without having to reduce the conveyor speed or use undesirableamounts of space in the facility or warehouse. The system also reducesthe amount of spacing between articles that is necessary. The conveyorsystem of the present invention therefore provides a design that enableshigher package throughputs to be achieved.

According to an aspect of the present invention, a conveyor sorter isprovided. The conveyor sorter includes a conveying surface that ismovable in a longitudinal direction. The conveyor further includes aplurality of diverting rails, a plurality of pusher shoes, and aplurality of diverters. The diverting rails extend diagonally under theconveying surface. The pusher shoes are capable of traveling across theconveying surface. Each pusher shoe includes an article contactingmember that extends at least partially above the conveying surface todivert articles on the conveying surface. The pusher shoes furtherinclude follower members extending at least partially below theconveying surface to engage selected ones of the diverting rails tolaterally displace articles on the conveying surface. The diverters areassociated with the diverting rails and each diverter is adapted toselectively transfer at least one of the follower members onto one ofthe diverting rails. A plurality of the diverting rails have at least afirst portion and a second portion. The first portion has a first anglewith respect to the longitudinal direction, and the second portion has asecond angle with respect to the longitudinal direction that isdifferent from the first angle.

According to yet another aspect of the present invention, a method isprovided for laterally displacing articles on a conveying surfacetraveling in a longitudinal direction. The method includes providing aplurality of pusher shoes, selecting particular ones of the pusher shoesto laterally displace an article on the conveying surface, and laterallydisplacing the selected pusher shoes. The lateral displacement of theselected pusher shoes is carried out at a first lateral rate during aninitial portion of travel of the selected pusher shoes, and at a secondlateral rate during a subsequent portion of the travel. The first andsecond rates are different from each other.

According to other aspects of the present invention, a third portion ofthe diverting tracks may be provided in addition to the first and secondportions. The first portion may be adjacent one of the diverters and thesecond portion may be adjacent a terminal portion of a diverting trackor rail. The first portion may have a greater or lesser angle than thesecond portion. The third portion may have the same angle as the firstportion, and the angle of the third portion may be substantially thesame as the angle of the take-away conveyor with respect to the mainconveyor. The activation of diverters into the diverting state may becarried out such that at least two diverters are activated which areseparated from each other by at least one non-activated diverter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a sortation conveyor to which may thevarious aspects of the present invention may be applied;

FIG. 2 is a perspective view of the underside of a pusher shoe which maybe used on the conveyor of FIG. 1, illustrated without a followerportion;

FIG. 3 is a side, elevational view of the pusher shoe of FIG. 2,illustrated with a follower portion attached;

FIG. 4 is a fragmentary, perspective view of a diverting assembly whichmay be used in accordance with the present invention;

FIG. 5 is a plan view of the diverting assembly of FIG. 4;

FIG. 6 is a top plan view of a sortation assembly for a conveyor systemaccording to one aspect of the invention, illustrated with a centerportion of the conveying surface removed to illustrate the underlyingstructure;

FIG. 7 is a top plan view, similar to FIG. 6, of a sortation assemblyfor a conveyor system according to another aspect of the invention;

FIG. 8 is a top plan view, similar to FIG. 6, of a sortation assemblyfor a conveyor system according to still another aspect of theinvention;

FIG. 9 is a top plan view similar to FIG. 6, of a sortation assembly fora conveyor system according to yet another aspect of the presentinvention;

FIG. 10 is a top plan view of a conveyor sortation assembly according tostill another aspect of the invention illustrating a diverting tracknetwork with dashed lines;

FIG. 11 is a flowchart of a first method for diverting an article fromthe conveyor; and

FIG. 12 is a flowchart of an alternative method for diverting an articlefrom a conveyor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described wherein the referencenumerals in the following written description correspond tolike-numbered elements in the several drawings. A sortation conveyor 12is depicted in FIG. 1. Sorter 12 is illustrative of the types ofconveyor sorters to which the various aspects of the present inventionfinds application. Conveyor 12 includes a conveying surface 18 definedby a series of surface members 24 that extend between sides 16 a and bof sorter 12. Surface members 24 move in a direction of conveyance 20,and thereby carry articles 74 in the same direction. When articles, suchas an article 74, are to be diverted off of conveyor 12 and onto one ormore branch conveyors 14 (FIG. 6), a plurality of pusher shoes 28 arediverted out of their longitudinal flow path and caused to traveltransversely across conveying surface 18. These shoes 28 impact thearticle and push it off of conveyor 12 onto the appropriate take-awayconveyor 14.

An example of one type of shoe 28 that may be used in the presentinvention is depicted in FIGS. 2–3. Shoes 28 are slidable along thelength of surface members 24 in a transverse direction 23. Shoes 28include a diverting portion 25 and a follower portion 27. Divertingportion 25 extends above surface member 24 and impacts articles whenthey are diverted. Follower portion 27, which may be attached via a pin29, or other means, extends below surface members 24 and selectivelyengages a series of guide tracks underlying conveying surface 18, aswill be explained more below. In the example of FIG. 3, follower portion27 is a toggle consisting of three bearings 31 a, b, and c. Followerportion could alternatively be constructed of a single bearing attachedto a pin, such as is disclosed in commonly-assigned U.S. Pat. No.5,127,510 issued to Cotter et al, entitled MODULAR DIVERTER SHOE ANDSLAT CONSTRUCTION, the disclosure of which is hereby incorporated hereinby reference. It will be understood that follower portion 27 may take onother constructions, as well.

Referring specifically to FIG. 6, a conveying system 10 includes a mainconveyor 12 and a branch conveyor 14. Additional branch conveyors beyondthe single branch conveyor 14 may be placed alongside main conveyor 12.The embodiment of FIG. 6 is illustrated for use with a unidirectionaldivert conveyor which diverts articles to one lateral side 16 a of aconveying surface 18. It should be understood that its principles mayalso be used with a bi-directional divert conveyor which divertsarticles selectively to either lateral side 16 a or 16 b of the conveyorsurface 18. An example of a bi-directional divert conveyor is depictedin FIG. 8. Branch conveyor 14 is positioned adjacent to main conveyor12, and at an angle α, as is conventional. Arrow 20 illustrates thedirection of conveyance for main conveyor 12. Arrow 22 illustrates thedirection of conveyance for branch conveyor 14.

As noted above, conveying surface 18 of main conveyor 12 is defined by aseries of surface members 24. The lengthwise direction of surfacemembers 24 is oriented perpendicular to the direction of movement 20 ofmain conveyor 12. Surface members 24 are supported on either side byside members 26 a and b. Surface members 24 may be connected to a motorby a chain or other means to propel them in the direction of conveyance20. The detailed construction of the conveying surface may take the formof that disclosed in U.S. Pat. No. 5,127,510, issued to Cotter et al.,although other constructions are possible. Alternatively, the surfacemembers 24 may be interconnected with each other and propelled by linearmotors, such as is disclosed in commonly-assigned InternationalApplication No. PCT/EP01/11264 (WO 02/26602 A2) filed Sep. 28, 2001,entitled POSITIVE DISPLACEMENT SHOE AND SLAT SORTER APPARATUS ANDMETHOD, the disclosure of which is hereby incorporated herein byreference.

The movable pushers, or diverting shoes, 28 are located along mainconveyor 12, opposite branch conveyor 14 and proximate to side member 26b. Diverting shoes 28 include a follower portion 27, such as adownwardly depending pin and attached bearing or other structure, thatcan be engaged by tracks lying underneath conveying surface 18, as willbe described more herein. As noted, diverting shoes 28 may be configuredlike those illustrated in FIGS. 2–3, or like those disclosed in theaforementioned U.S. Pat. No. 5,127,510, or the aforementionedInternational Patent Application No. PCT/EP01/11264 (WO 02/26602 A2), orthey may take on other forms. When diverting shoes 28 are not displacingan article off main conveyor 12 and onto branch conveyor 14, they travelin sequence along a shoe guideway 30, adjacent a longitudinallyextending guide track 32. Guide track 32 prevents diverting shoes 28from moving transversely across main conveyor 12 by blocking lateralmovements of the bearings or other structures that extend downward fromthe shoes 28. Only at the point along main conveyor 12 at whichdiverters 34 a through 34 d are located, or along similar points where abranch conveyor connects to main conveyor 12, are shoes 28 free to movelaterally.

Diverters 34 a through 34 d can be seen attached along side member 26 bof main conveyor 12, and in the path of diverting shoes 28. Diverters 34a through 34 d may be of the type disclosed in commonly-assigned U.S.Pat. No. 5,038,912, issued to Cotter, U.S. Pat. No. 5,409,095, issued toHoshi et al., U.S. Pat. No. 6,615,972, issued to Veit et al. orInternational Patent Application No. PCT/EP01/04746 (WO 01/83342) filedApr. 26, 2001, entitled SORTATION SYSTEM DIVERTER SWITCH, thedisclosures of which are hereby incorporated herein by reference. Otherdiverters known in the art may also be used.

One embodiment of diverters 34 that may be used in accordance with thepresent invention is depicted in FIGS. 5 and 6. Four diverters 34 a–dare depicted in each of these drawings. Diverters 34 a–d each include anelectromagnet 35 that is positioned adjacent guideway 30. Eachelectromagnet 35 is selectively energizable. When energized, themagnetic field created by electromagnet 35 creates an attractive forcethat attracts follower portion 27 of diverting shoes 28. This attractiveforce causes follower portion 27 to switch from traveling along guideway30 to traveling along one of the diverting tracks 38 that is closest tothe activated electromagnet 35. When an article is to be diverted fromconveying surface 18, one or more selected diverters 34 are activated byenergizing their associated electromagnet 35. After the appropriatenumber of shoes 28 have been diverted, the electromagnet 35 isde-energized, and subsequent shoes 28 that travel by the electromagnet35 are not diverted.

With reference to FIGS. 6–10, a section of conveying surface 18 has beenremoved from the central portion of main conveyor 12 to illustrate thestructure of an underlying diverting track network 36. Diverting tracknetwork 36 includes a plurality of diverting tracks 38. While FIGS. 6–10depict four diverting tracks 38, it will be understood by one skilled inthe art that the invention is not limited to four diverting tracks.Instead, other numbers of diverting tracks can be used. In theembodiment depicted in FIG. 6, each diverting track 38 includes a firstportion 40 and a second portion 42. First portion 40 is locatedgenerally adjacent diverters 34 a–d. First portion 40 extends fromdiverters 34 a–d to an imaginary dividing line 44. Second portion 42extends from dividing line 44 to the terminal end of diverting tracks38, which is located generally adjacent branch conveyor 14. Firstportion 40 is oriented at an angle ψ with respect to the longitudinaldirection of main conveyor 12. Second portion 42 of diverting tracks 38is orientated at an angle θ with respect to the longitudinal direction20 of main conveyor 12. Angle θ is different than angle ψ. Asillustrated, first portion 40 has a steeper or larger angle than secondportion 42, that is, angle ψ is greater than angle θ. Assuming aconstant longitudinal speed of main conveyor 12, diverting shoes 28 willmove laterally from side 16 b towards side 16 a at a slower rate whenthey are traveling along second portion 42 than when they are travelingalong first portion 40. Thus, diverting shoes 28 will initially movelaterally at a higher speed until they reach imaginary dividing line 44.When they reach dividing line 44, their lateral speed will decrease asthey move along second portion 42 of the diverting tracks 38. The impactof the diverting shoes 28 against an article to be diverted, which willoccur along second portion 42, will therefore be less than it would beif the diverting shoes 28 were to impact against an article in firstportion 40.

First portion 40 of diverting tracks 38 is generally oriented at agreater or steeper angle than second portion 42 in order to accommodatethe physical construction of diverters 34 a–d. Diverters 34 a–d maygenerally require that first portion 40 of diverting tracks 38 beoriented at a steeper angle in order to provide sufficient space fordiverters 34. Having a first portion 40 of diverting tracks 38 with agreater angle therefore provides more space to accommodate diverters 34a–d. This may simplify the construction of diverters 34. However, as hasbeen noted previously, this steeper angle leads to greater speeds ofdiverting shoes 28 in first portion 40. Therefore, conveying system 10may be designed to generally prevent articles from traveling closer toconveyor side 16 b than dividing line 44. Stated alternatively,conveying system 10 may be designed so that articles are positioned on aside of dividing line 44 opposite diverters 34 a–d. Such a design can beaccomplished in any conventional manner. By designing conveying system10 in this manner, the articles traveling on conveying surface 18 willnot be impacted by diverting shoes 28 when they are traveling alongfirst portion 40. The articles will therefore only be impacted bydiverting shoes 28 when these shoes are traveling at the slower lateralspeed associated with second portion 42. The impact against the articlesby diverting shoes 28 is therefore lessened.

It will be understood that the precise angles of first and secondportions 40 and 42 can be varied as desired. Angle ψ of first portion 40should be chosen in order to accommodate whatever diverters 34 are beingused in conveying system 10. Angle θ of second portion 42 may, althoughnot necessarily, be oriented at an angle that is equal to angle ψ theorientation of take-away conveyor 14. In this manner, articles that arediverted using diverting tracks 38 may be reoriented so that theirlongitudinal direction is essentially parallel to direction 22,depending on how diverters 34 are activated. As one possible example,angle ψ may be 30 degrees and angle θ may be 25 degrees. Other examplesare, of course, possible.

The timing and manner in which diverters 34 are activated into adiverting state can be varied as desired in the system depicted in FIG.6. Various different protocols for selecting which diverters 34 toactivate, the timing of the activation, and the length of theactivation, are described in further detail herein. These methods may beused in conjunction with conveying system 10, although other methods ofcontrolling diverters 34 can also be used.

A conveying system 110 according to another embodiment of the presentinvention is depicted in FIG. 7. Components in conveying system 110 thatare the same as the components in system 10 bear the same referencenumeral. Components in conveying system 110 that are modified from thecomponents in conveying system 10 include the same reference numeralsummed together with the number 100. New components in conveying system110 that do not appear in system 10 bear new reference numerals.Conveying system 110 generally differs from conveying system 10 in theconstruction of diverting tracks 38 and the orientation of branchconveyor 14. Diverting tracks 138 include a first portion 140, a secondportion 142, and a third portion 146. An imaginary dividing line 144separates first and second portions 140 and 142. Another dividing line148 separates second portion 142 from third portion 146. First portion140 is angled with respect to the longitudinal direction of conveyanceat an angle ψ. Second portion 142 is angled with respect to thelongitudinal direction of conveyance 20 at an angle θ. Third portion 146is angled with respect to the longitudinal direction of conveyance 20 atan angle ε. Angles ψ and θ may be the same or different from the anglesψ and θ illustrated in FIG. 6. Angle θ, however, is preferably less thanangle ψ, as well as angle ε. The angles ψ and ε of first portions 140and third portions 146, respectively, may be the same as each other, ordifferent.

Like system 10, conveying system 110 may be configured so that articlestraveling on main conveyor 12 do not travel over portions of conveyingsurface 18 that underlie first portion 140 of diverting tracks 138. Inthis manner, articles are not initially impacted by diverting shoes 28that are traveling at the relatively higher lateral speed associatedwith first portion 140. Rather, articles traveling on conveying surface18 are initially impacted by diverting shoes 28 traveling at therelatively slower speed associated with second portion 142. Afterarticles are initially impacted and moved by diverting shoes 28traveling at second portion 142, they experience an increased force whenthe diverting shoes reach dividing line 148. This increased force iscaused by the different angular orientation of diverting tracks 138 inthird portion 146.

Angle ε of diverting tracks 138 in third portion 146 may generallycorrespond to angle β illustrated in FIG. 7. The increased angle ε ofthird portion 146 allows articles to exit main conveyor 12 onto branchconveyor 14 with a higher lateral speed than what they experience fromsecond portion 142. This higher lateral speed allows the effective widthof branch conveyor 14 to be less. Specifically, the distance Billustrated in FIG. 7 is less than the distance A illustrated in FIG. 6.This is because branch conveyor 114 in FIG. 7 has a greater angle (β)than branch conveyor 14 does in FIG. 6 (α). Because branch conveyor 114takes up less linear space along side 16 a of main conveyor 112, it ispossible to more closely pack together multiple branch conveyors 114along main conveyor 112. The amount of floor space occupied by theoverall conveying sortation system is therefore reduced. Further,because of the construction of diverting tracks 138, the articles beingdiverted in conveying system 110 are not subjected to excessive impactsor rotational forces. This is due to the fact that the articles are onlyinitially impacted by the relatively slow moving diverting shoestraveling in second portion 42. While the articles experience increasedforces when they reach third portion 146, the difference in speeds andforces between second portion and third portion 146 is significantlyless than if the articles were initially impacted by shoes traveling ina diverting track having an angle equal to that of third portion 146.Conveying system 110 can therefore utilize branch conveyors 114 orientedat greater angles, while still not subjecting diverted articles to undoforces that might otherwise cause toppling, excessive rotation, or otherdisruptions. Conveying system 110 can therefore accommodate more branchconveyors 114 along a given length the main conveyor 12 than wouldotherwise be possible.

A conveying system 210 according to another aspect of the presentinvention is depicted in FIG. 8. Those components in conveying system210 that are identical to those components in conveying system 10 areidentified by the same reference numeral. Modified components inconveying system 210 use the same reference numeral as conveying system10, with the exception that the number 200 has been added to them. Newcomponents are labeled using entirely new reference numerals. As hasbeen mentioned previously, conveying system 210 is a bi-directionaldiverting conveying system. Stated alternatively, main conveyor 12 ofconveying system 210 includes branch conveyors 214 a and b positioned onboth sides 16 a and b. Thus, articles can be diverted off to both branchconveyor 214 a and branch conveyor 214 b. Conveying system 210 includesfour diverters 234 a–d positioned along side 16 b. Conveying system 210further includes four diverters 234 e–h positioned along side 16 a ofmain conveyor 12. Shoes 28 that are positioned upstream of diverters 234travel along either side 16 a or b of main conveyor 12. If an article isto be diverted down branch conveyor 214 b, an appropriate number ofdiverting shoes 28 must be traveling adjacent side 16 a at theappropriate time so that diverters 234 e–h can be used to divert theseshoes.

As illustrated in FIG. 8, there are four diverting tracks 238 associatedwith each set of diverters 234 a–d and 234 e–h. Diverting tracks 238 aregenerally constructed in a manner similar to diverting tracks 38.Specifically, diverting tracks 238 each include a first portion 240 anda second portion 242. A dividing line 244 separates the first and secondportions for each of these diverting tracks 238. First portion 240 isangled at a greater angle than second portion 242.

Each set of four diverting tracks 238 extends laterally across mainconveyor 12 between sides 16 a and b. The diverting tracks 238associated with diverters 234 a–d intersect the diverting tracks 238associated with diverters 234 e–h. These intersections are labeled 250.Intersections 250 are adapted to allow shoes to keep traveling along thediverting track 238 which they originally started traveling along andare well known in the art.

Articles traveling on conveying surface 18 that are to be diverted downbranch conveyor 214 b are preferable positioned on the side of the upperdividing line 244 (FIG. 8) opposite diverters 234 e–h. In this manner,such articles will not be impacted by diverting shoes 28 that are movingat the relatively higher lateral speed associated with first portions240. Conveyor system 210 ensures that diverting shoes 28 are positionedon the proper side of conveyor 12 for the appropriate diverts in anyknown manner.

A conveying system 410 according to another aspect of the presentinvention is depicted in FIG. 10. Components of system 410 in commonwith system 10 bear the same reference numeral while modified componentsbear the same number summed with 400. System 410 includes a plurality ofdiverting tracks 438. Each diverting track 438 includes a first section440 and a second section 442. First section 440 is oriented at an angleψ with respect to the direction of conveyance 20. Second section 442 isoriented at an angle θ with respect to the direction of conveyance 20.In system 410, angle ψ is less than angle θ. Thus, shoes 28 travelingalong first section 440 will travel at a slower lateral speed than theywill when traveling along second section 442. Angle θ may, for example,have a value as high as 45 degrees, or more.

Conveying system 410 is especially suitable to conveyor sortationapplications in which the sortation system is run at relatively slowspeeds. The relatively slower speeds allow second section 442 to have asteeper angle θ than they otherwise would have in a faster system.Because conveyor 12 is run at a slower speed, the increased angle θ willnot give the shoes 28 such a high lateral speed as to cause toppling orother undesired movement of the articles being diverted. The operationof the sortation system at a relatively slower speed allows branchconveyor 14 to be positioned at a steeper angle with respect to mainconveyor 12. This steeper angle allows more branch conveyors 14 to bepositioned alongside main conveyor 12 over a given longitudinal extentof conveyor 12.

First section 440 in conveying system 416 is oriented at a smaller angleψ than angle θ for multiple reasons. The smaller angle ψ reduces thestresses that are placed upon the follower portions 27 as they arediverted by diverters 34. Likewise, the stresses that are placed uponthe diverters 34 by the impinging followers portions 27 are alsoreduced. Further, the smaller angle ψ may be desirable because diverters34 may be a standard component that is desirably manufactured for usewith different types of sortation systems. By constructing divertingtracks 438 in the manner illustrated in FIG. 10, the same diverters 34that are used in higher speed sortation systems, like those of FIGS.6–9, could also be used in system 410.

An imaginary dividing line 44 separates first sections 440 from secondsections 442. If a follower portion 27 having three bearings 31 is usedwith conveyor system 410, system 410 may advantageously be designed sothat shoes 28 do not impact against articles until after they havecompletely transitioned from first section 440 onto second section 442.During this transition, the two outside bearings 31 a and c will bearagainst first section 440 and second section 442, respectively. Themiddle bearing 31 b will temporarily be out of contact with any guidetrack, due to the sharpness of the angular transition between first andsecond sections 440 and 442. Depending on the construction of followerportion 27, it may be undesirable to solely have outside bearings 31 aand c bear the load of diverting a package. To avoid this situation,system 410 may be designed so that articles always enter conveyor 12 onthe side of imaginary line 44 that is closer to side 16 a.

Another conveyor system 310 is depicted in FIG. 9. Components of system310 in common with system 10 bear the same reference numeral whilemodified components bear the same number summed with 300. Conveyorsystem 310 includes four diverting tracks or rails 338 that aregenerally straight and parallel to each other for substantially theirentire length. The downstream ends of diverting rails 338 may be curvedin order to reduce the impact of the follower portion 27 with side 16 aof the conveyor 12. Alternatively, a noise and wear reducing apparatus,such as that disclosed in commonly assigned U.S. Pat. No. 5,732,814issued to Owczarzak et al., the disclosure of which is herebyincorporated by reference, may be placed adjacent each terminal end ofdiverting rails 338 in order to lessen the noise and wear of followerportions 27 impacting the side of the conveyor. The same apparatus maybe used at the terminal end of the diverting tracks in any of the otherembodiments of the invention described herein in order to reduce noiseand wear. Conveyor system 310 differs from the preceding embodiments inthat the diverting rails 338 have only one divert angle. However, aswill be explained below, control techniques are provided to enhancesystem throughout. It should be understood that these techniques canalso be provided to the previously illustrated embodiments.

The various conveyor systems 4 through 410 may be equipped with at leastone sensor 52, operably connected to a control system 60, to therebydetermine the length of each package being transported along theconveyor system. Sensor 52 may be any sensor commonly used in the art,such as photosensors, and is positioned in proximity to, or along mainconveyor 12, preferably upstream of diverting track network 36 of mainconveyor 12. Control system 60 is in electrical communication with adivert control module 58. Divert control module 58 oversees the actualactivation of diverters 34 into their diverting state based on commandsreceived from controller 60. Control system 60 and divert control module58 may be of the type disclosed in commonly assigned U.S. patentapplication Ser. No. 10/163,788 by Zeitler et al. for a TIERED CONTROLARCHITECTURE FOR MATERIAL HANDLING, the disclosure of which is herebyincorporated by reference.

When a particular package or article is to be diverted onto branchconveyor 14, divert control module 58 causes the selective actuation ofone or more diverters 34. In one embodiment, divert control module 58may simultaneously activate two or more diverts 34 to cause an articleto be diverted. In such a system, controller 60 may cause the divertcontrol module 58 to effect actuation of the diverter 34 that isfarthest downstream along main conveyor 12, when the leading end of apackage is adjacent to it. Simultaneously, controller 60 will cause thedivert control module to actuate an upstream diverter 34 along acorresponding upstream diverting track 38. The upstream diverter 34 thatwill be selected may be whichever is most proximate to the trailing endof the package. The activation of the diverters 34 into their divertingstate may be carried out only for so long as necessary to allow a singleshoe 28 to be diverted to a corresponding diverting track.

Although the invention is illustrated in FIG. 9 with two shoes beingdiverted to divert a package, any of the various embodiments of thepresent invention could utilize three or more diverting shoes for eachpackage. Preferably, to the extent the article to be divertedsubstantially exceeds the length of two pushers, it is diverted usingtrailing and leading diverters which are separated by at least oneintermediate diverter which is not activated into the diverting state.Where the article does not exceed the length of two pushers, twoadjacent diverters may be used to divert the article. The invention isnot intended to be limited by the configuration of the diverting shoe28, the surface members 24, or the diverters 34.

In another embodiment of the present invention, controller 60 may usecontrol logic 61 (FIG. 12). Control logic 61 is applicable to any of theconveying systems depicted and described herein, as well as to otherconveying diverting assemblies, but is illustrated with reference toFIG. 9. Control logic 61 can activate only one diverter 34 to rotate anddiagonally divert an article using conventional divert techniques suchas disclosed in the '510 patent, can simultaneously activate two or morediverters 34 to divert an article entirely without rotation, or candelay the activation of the upstream diverter 34 for a variable lengthof time to partially rotate an article. This delay may be especiallyuseful to accommodate widely varying lengths of articles without havingto install as many diverters 34 and their associated diverting tracks 38as the maximum length of packages would otherwise require wherediverters are activated simultaneously. For example, if the maximumexpected article length is three feet, and each diverter 34 can bespaced apart 4 inches, then a total of nine diverters 34 and theirassociated diverting tracks could be accommodated in the diverting area.However, nine diverters and diverting tracks may be undesirablyexpensive. In order to still be able to accommodate three foot longarticles, a lesser number of diverters and diverting tracks could beused and spaced in a more compact area, such as a two foot area. In sucha situation, control logic 61 would activate the downstream diverterwhen the leading edge of the article was adjacent to this downstreamdiverter. If the article were three feet long, the trailing edge of thearticle would not be adjacent the most upstream diverter at this timebecause the most upstream diverter is only two feet away from thedownstream diverter. The activation of the most upstream diverter istherefore delayed until sufficient time has passed for the article'strailing edge to have moved adjacent the most upstream diverter. At thatmoment, the most upstream diverter is activated by control logic 61. Thedelay between the time the downstream diverter is activated and the timethe upstream diverter is activated is dependent upon the speed of theconveyor as well as the length of the article being diverted relative tothe distance between the upstream and downstream diverters.Alternatively, the delay between activating a first and second divertercan be increased such that the second diverter activated is notnecessarily the most-upstream diverter, but may instead be anotherdiverter. The activation of diverters 34 may be carried out so that onlya single shoe 28 is diverted by each activated diverter 34.

An example of a partial-rotation divert being carried out by controllogic 61 is depicted in FIG. 9. When the leading edge of the article tobe diverted was adjacent downstream diverter 34 a, diverter 34 wasactivated. At that time, controller 60, using control logic 61,activated only diverter 34 a into a diverting state. This caused asingle follower portion 27 a of a shoe 28 to be diverted down thedownstream-most diverting track 338. Controller 60 delayed activatingdiverter 34 d into the diverting state until the trailing edge of thearticle had traveled sufficiently far so as to reach, or be adjacent to,diverter 34 d. As illustrated, the activation of diverter 34 d wasdelayed, by way of example, for the amount of time after diverter 34 awas activated that it took for one surface member 24 to have passed bydiverter 34 d. This delay may be a function of the length of articlebeing diverted utilizing a partial rotation. This is illustrated byfollower member 27 b, which is traveling adjacent the upstream-mostdiverting track 338.

Control logic 61 is diagrammed in FIG. 12. At block 62, the length ofthe next article to be diverted is determined. This length may bedetermined via sensor 52, or by any other suitable means. Based on thedetermined length of the next article to be diverted, control logic 61will activate diverters 34 in different manners, as will now bedescribed. At decision point 64, control logic 61 determines if thelength of the next article to be diverted exceeds a distance A or not.If it is less than distance A, the article is diverted at step 66without rotating it. Such a non-rotational diversion can be accomplishedin any suitable manner such as, for example, by activating two or morediverters 34 substantially simultaneously. Because diverting tracks38–438 are generally parallel to each other, the substantiallysimultaneous activation of two or more of these diverters 34 will causethe article to be diverted without rotation. Preferably the two or morediverters 34 to be activated include one diverter 34 that is adjacentthe upstream edge of the article and one diverter 34 that is adjacentthe downstream edge of the article.

If the length of the article to be diverted exceeds the distance A, thencontrol passes to decision point 68. Decision point 68 determineswhether or not the length of the article to be diverted falls betweenlengths A and B, with length B being greater than length A. If thelength of the article falls between lengths A and B, the article isdiverted at step 71 with partial rotation. The partial rotation of thearticle may be accomplished by activating two of diverters 34 into thediverting state at different times. In one embodiment, a diverter 34adjacent the downstream end of the article is first activated into thediverting state. Thereafter, a second diverter 34 that is upstream ofthe activated diverter 34 is also activated into the diverting state.The second activated diverter 34 may desirably be adjacent the upstreamedge of the article to be diverted when it is activated into thediverting state. For example, in the conveying system 10, diverter 34 amay first be activated when the downstream edge of the article isadjacent diverter 34 a. The activation of diverter 34 a will cause atleast one shoe 28 to be diverted along the corresponding diverting track38. This at least one shoe will exert a rotational force onto thearticle being diverted, thereby causing it to rotate. When the trailingedge of the article reaches one of the upstream diverter 34 b–d, it isactivated. This causes a shoe to follow along one of the correspondingupstream diverting tracks 38. This shoe will exert a force on thearticle that tends to stop the rotation of the article. The article willthus be diverted by experiencing a rotational force for an initial timeperiod followed by a generally non-rotational force for a subsequenttime period. The selected upstream diverter may be based on the closestdivert 34 to the trailing edge of the article at the time that theamount of delay has expired.

If the length of the article is determined at step 68 to not lie betweenlengths A and B, then it must be greater than length B. In thissituation, the article is diverted with full rotation at step 72. Thisdiverting is carried out by activating only a single diverter 34. Whilethe single diverter 34 that is to be activated may desirably be the mostdownstream diverter (diverter 34 a in FIG. 6), the inventioncontemplates activating other diverters 34. The activation of the singlediverter 34 can be maintained to allow more than one shoe 28 to bediverted onto a diverting track 438 a. Alternatively, only a single shoe28 may be diverted. Because no other diverters are activated in thismethod of diverting, the article will continue to experience arotational force until it is rotated generally parallel to the finalangle of the diverting track 38.

Distance A of FIG. 12 may be based upon the width of the conveyingsurface of branch conveyor 14. Because articles will be diverted withoutrotation by control system 60 when they are less than distance A, thesearticles will enter branch conveyor 14 with an orientation that is notparallel to the longitudinal extent of branch conveyor 14. Thisorientation will increase the effective width of the article withrespect to the branch conveyor 14. The effective width of the articlerefers to the total distance in the longitudinal direction that anarticle will travel from the time an initial portion of the article ispushed off of main conveyor 12 until it is completely pushed off ofconveyor 12. If the effective width of the article is greater than theactual width of branch conveyor 14, the article may not fit onto branchconveyor 14 without rotating, jamming, or falling off of the conveyors.Distance A should therefore be set at an amount that prevents thesepotential problems. Distance A may also be based partially upon thelongitudinal distance between two shoes that are simultaneouslyactivated by the most upstream and most downstream diverters 34. Ifarticles exceed this length by too great a distance, then thesimultaneous activation of two or more diverters 34 may undesirablycause the article to rotate, depending upon where the shoes 28 impactthe article in relation to the article's center of gravity. Distance Amay therefore be limited by both the width of the branch conveyor 14 andthe longitudinal distance between simultaneously activated shoes on theupstream and downstream-most diverting tracks 38.

Distance B of FIG. 12 may be based upon article lengths that have thepotential to jam if they are diverted without rotation for anysubstantial length of time. In general, these articles will berelatively long articles. In order to prevent this potential jamming,articles that exceed length B should be diverted using only a singlediverter 34, which is preferably, although not necessarily, the mostdownstream diverter 34 in the diverting assembly.

It will be understood that the control logic followed by control system60 can be implemented on diverting assemblies that vary from thosedepicted in FIGS. 6–10. For example, control system 60 can use thecontrol logic described herein on any of the diverting assembliesdisclosed in commonly assigned U.S. Pat. No. 6,513,642, issued to JamesT. Shearer, Jr. et al., the disclosure of which is incorporated hereinby reference. It can also be used with still other diverting assemblies.Control logic 61 can also be modified to not include steps 68 and 72.With such a modified system, any articles that exceeded the length Awould be diverted with partial rotation. Alternatively, steps 68 and 71of control logic 61 could be eliminated. Other variations are alsopossible.

Another example of control logic 70 that may be used in any of theembodiments described herein for carrying out diverts is depicted inFIG. 11. Control logic 70 carries out partial-rotation diverts ornon-rotation diverts. Logic 70 first determines at block 76 when theleading edge of the article to be diverted is adjacent the mostdownstream diverter. At that moment, control logic 70 activates thedownstream diverter in block 78. At block 80, control logic 70 alsodetermines if the trailing edge of the article is adjacent any divertersand, if so, activates the diverter adjacent the trailing edge at block82. Where the trailing edge of the article is adjacent an upstreamdiverter at the same time the leading edge is adjacent the downstreamdiverter, the activation of the upstream and downstream diverters inblocks 78 and 82 occurs substantially simultaneously. If, at block 80,it is determined that the trailing edge of the article is not adjacentany upstream diverter, this is due to the article being longer than thelength of the diverter array. In this case, control passes to block 84where control logic 70 waits until the trailing edge of the articlearrives at a location adjacent a selected upstream diverter. Controllogic 70 then activates the selected upstream diverter at block 86 andcontrol returns to block 76 for the next article to be diverted. Theselected upstream diverter may preferably be the upstream-most diverter34, although other diverters could be selected.

As noted, control logic 70 determines whether to activate diverterssimultaneously or non-simultaneously based on the length of the article.By choosing between non-simultaneous and simultaneous diverteractivation, control logic 70 allows the conveying system to divertarticles that exceed the maximum distance between the furthestdownstream diverter 34 and the furthest upstream diverter 34 in aparticular diverting area. While the non-simultaneous diverting ofpusher shoes will result in the article experiencing an initialrotational force, such rotation may be acceptable in order to limit theexpenses by reducing the number of diverters and their associateddiverting tracks. Further, by reducing or eliminating the amount ofrotation of articles being diverted, the spacing between articles can bereduced, thereby increasing the throughput of the system. Control logic70 may be used with any of the diverting track configurations depictedin the attached drawings, or still other configurations.

In determining whether an article's leading or trailing edge is adjacenta diverter, one or more sensors 52, such as a photo-eyes or otherconventional sensors, may be used. Such sensors can be placed at an anyknown location and may be used in combination with other sensors, suchas encoders that measure the movement of the conveying surface, todetermine an article's position and/or length.

According to another embodiment of the invention, another method ofselecting which diverters 34 to activate into a diverting state takesinto account the axis of rotation of the articles to be diverted. Inthis method, controller 60 selects which one or ones of diverters 34 toactivate based on the location of the axis of rotation of an articlerelative to the position of the diverters 34. Controller 60 selectsdiverters 34 so that an article is impinged by pusher shoes 28 thatimpact the article along its side in at least one location that isupstream of the axis of rotation and at least one location that isdownstream of the axis of rotation. By selecting shoes in this manner,the article will experience a force that is generally balanced on eitherside of the axis of rotation so that it will not rotate more than thatallowed by pusher shoes 28.

For example, suppose an article is to be diverted that has an eight inchlength, that the longitudinal extent of pusher shoes 28 is six inches,and that this six inch extent is centered over, and doesn't extendbeyond, each surface member 24. Suppose further that the axis ofrotation of the article passes precisely through the center of thearticle. Controller 60 receives information from sensor 52, or otherknown sensors, that tells it where the article is located with respectto the underlying surface member 24. If the axis of rotation of thearticle lies right between two adjacent surface member, then controller60 determines that the article will have to be diverted by activatingtwo diverters 34. Activating only a single diverter in this case wouldcause only about half of the pusher shoe's longitudinal extent (3 inchesin this example) to impact the article, because the shoes are centeredon the surface members and don't extend substantially beyond the edgesof the surface members. This impact would occur along either the frontthree inches or rear three inches of the eight inch article, dependingon which diverter 34 was activated. Because the force of the pusher shoe28 would be entirely upstream or entirely downstream of the pusher shoe,but not both, the force against the article would be imbalanced, and thearticle would rotate. This rotation might be so great as to cause thearticle to rotate out of contact with the pusher shoe 28, in which casethe article would likely not be diverted to the branch conveyor 14.Therefore controller 60 activates two diverters 34 so that the articleis impinged by pusher shoes 28 both upstream and downstream of the axisof rotation.

As another example, suppose the axis of rotation of a eight inch articlewas precisely centered over a surface member 24. In this case,controller 60 selects only a single diverter 34 to be activated becausea single pusher shoe 28 will impact the article both three inchesforwardly of the axis of rotation and three inches rearwardly of theaxis of rotation. The article will therefore not rotate because it isbeing impacted on both sides of its axis of rotation. Controller 60therefore selects which diverters to activate based on the location thatthe pusher shoes will impact the article. Controller 60 selects thediverters so that the one or more pusher shoes that are diverted willimpact locations on the article that are both upstream and downstream ofthe axis of rotation. Controller 60 may be programmed to divertsufficient shoes 28 so that the article is contacted at least one inchupstream and one inch downstream of its axis of rotation.

By selecting diverters 34 based on the article's axis of rotation, theinter-package spacing between articles can be reduced. For example, inthe situation described above where the eight inch article is divertedby two diverters 34, the package will desirably have at least two inchesof separation from both the upstream and downstream adjacent articles.Any less spacing than this will cause the two pusher shoes 28 that arediverted to impact against the adjacent articles, which is generallyundesirable. However, in the situation where only a single shoe 28 isused to divert the article, the adjacent articles can have little or nospacing between themselves and the article being diverted. This isbecause the single shoe does not extend beyond either the forward orrearward edges of the article being diverted, and therefore will notimpact against either of the adjacent articles. Articles can thus bemore closely spaced where the activated diverting shoes 28 do not extendbeyond the edges of the article being diverted, or where the amount ofthis extension is known and can thus be accommodated.

The determination of the article's axis of rotation can be performedupstream of conveyor 12 in any suitable fashion. This information isthen transmitted to controller 60. As one example, the article's axis ofrotation can be assumed to be aligned with the control point of anarticle as defined in commonly-assigned U.S. Pat. No. 6,629,593, issuedto David W. Zeitler, the disclosure of which is hereby incorporatedherein by reference. Controller 60 therefore chooses diverters 34 sothat shoes 28 impact against both upstream and downstream locations onthe article relative to this control point. Other methods may also beused.

It will be understood by one skilled in the art that the junctions ofthe various portions 40, 42, and 46 of diverting tracks 38 canpreferably be modified from that illustrated. Specifically, the variousdrawings illustrate these sections to be entirely linear such that theirjunctions form sharp angles or edges. The junctions between each ofthese portions may advantageously be modified so that a more curved orgradual junction is defined between each portion. Using curved junctionsbetween the portions of the diverting tracks 38 will reduce the wear andtear of both the guide-track following portion of the shoes 28, as wellas the wear and tear of the guide tracks themselves. In addition to areduction in wear and tear, smoothing the transitions between thediverting track portions will also likely reduce the noise created bythe diverting conveying system.

Having described the invention in connection with certain specificembodiments thereof, it is to be understood that the description ismeant to be interpreted as illustrative only, and that variousmodifications may also be made by those skilled in the art withoutdeparting from the spirit and scope of the invention as expressed in theaccompanying claims.

1. A conveyor sorter, comprising: a conveying surface movable in alongiudinal direction; a plurality of pusher shoes capable of travelinglaterally of said conveying surface; at least one diverting railconfigured to selectively guide at least one of said pusher shoeslaterally of said conveying surface; and at least one diverterassociated with said at least one diverting rail, said at least onediverter adapted to selectively transfer the at least one of said pushershoes to said at least one diverting rail; wherein said at least onediverting rail having at least a first portion adjacent said at leastone diverter and a second portion extending from an end of said firstportion away from said at least one diverter, said first portion havinga first angle with respect to said longitudinal direction and saidsecond portion having a second angle with respect to said longitudinaldirection that is different from said first angle, wherein the at leastone of said pusher shoes guided by said at least one diverting railinitially contacts an article on said conveying surface at said firstportion, wherein said first angle configured to produce a first lateralforce of the at least one of said pusher shoes contacting an article,said second angle configured to produce a second lateral force of the atleast one pusher shoe wherein said second lateral force is higher thansaid first lateral force.
 2. The sorter of claim 1 including a control,said control sensing said pusher shoes and selectively operating said atleast one diverter to selectively transfer at least one of said pushershoes to said at least one diverting rail.
 3. The sorter of claim 1wherein said at least one diverting rail is at least partialiy curved.4. The sorter of claim 1 including a gradual junction between said firstportion and said second portion.
 5. The sorter of claim 1 wherein saidsecond portion is adjacent a terminal portion of said at least onediverting rail.
 6. The sorter of claim 1 further including a branchconveyor extending at an angle from a lateral side of said sorteropposite from said at least one diverter, said second portion of said atleast one diverting rail being substantially parallel to a longitudinalcenter-line of said branch conveyor.
 7. The sorter of claim 1 whereinsaid at least one diverting rail comprises a plurality of divertingrails and said at least one diverter comprises a plurality of divertersand further wherein said plurality of diverting rails are generallyparallel to each other.
 8. The sorter of claim 7 wherein said pluralityof diverting rails and said plurality of diverters cooperate to divertan individual article.
 9. The sorter of claim 8 wherein said pluralityof diverting rails and said plurality of diverters divert an individualarticle without substantial rotation of that article.
 10. The sorter ofclaim 8 wherein said plurality of diverting rails and said plurality ofdiverters divert an individual article with an initial rotation of thatarticle.
 11. The sorter of claim 7 further including a controlleradapted to cause at least two of said diverters to substantiallysimultaneously transfer at least two of said pusher shoes onto at leasttwo of said diverting rails.
 12. A method of laterally displacingarticles, said method comprising: providing a conveying surfacetraveling in a longitudinal direction; providing a plurality of pushershoes; selecting particular ones of said pusher shoes to laterallydisplace an article on said conveying surface; and laterally displacingthe particular ones of said pusher shoes including initially impactingan article with the particular ones of said pusher shoes andsubsequently displacing the article after said impacting with theparticular ones of said pusher shoes, said impacting comprisinglaterally displacing the particular ones of said pusher shoes at a firstlateral rate, said subsequently displacing comprising laterallydisplacing the particular ones of said pusher shoes at a second lateralrate, said second lateral rate being higher than said first lateralrate.
 13. The method of claim 12 including providing a branch conveyorextending laterally at an angle to said conveying surface, wherein saidsecond lateral rate causing the article to align with said branchconveyor.
 14. The method of claim 12 including laterally displacing anarticle without substantial rotation of that article.
 15. The method ofclaim 12 including laterally displacing an article with at least apartial initial rotation of that article.
 16. The method of claim 12including providing a gradual transition between said first lateral rateand said second lateral rate.
 17. A method of laterally displacingarticles, said method comprising: providing a conveying surfacetraveling in a longitudinal direction and a plurality of pusher shoescapable of traveling laterally of said conveying surface; providing atleast one diverting rail and selectively guiding at least one of saidpusher shoes laterally of said conveying surface with said at least onediverting rail; providing at least one diverter associated with said atleast one diverting rail and selectively transferring the at least oneof said pusher shoes to said at least one diverting rail with said atleast one diverter; wherein said at least one diverting rail having atleast a first portion adjacent said at least one diverter and a secondportion extending from an end of said first portion away from said atleast one diverter; said selectively guiding including initiallyimpacting an article with the at least one of said pusher shoes andsubsequently displacing the article after said impacting with the atleast one of said pusher shoes, said impacting comprising laterallydisplacing the at least one of said pusher shoes at a first lateralrate, said subsequently displacing comprising laterally displacing theat least one of said pusher shoes at a second lateral rate, said firstlateral rate causing the at least one of said pusher shoes to apply animpact force to the article, said second lateral rate causing the atleast one of said pusher shoes to apply a subsequent force to thearticle, said subsequent force being higher than said impact force. 18.The method of claim 17 wherein said second portion is adjacent aterminal portion of said at least one diverting rail.
 19. The method ofclaim 17 including providing a branch conveyor extending at an anglefrom a lateral side of said conveying surface opposite from said atleast one diverter, said second portion of said at least one divertingrail being substantially parallel to a longitudinal center line of saidbranch conveyor.
 20. The method of claim 17 wherein said at least onediverting rail comprises a plurality of diverting rails and said atleast one diverter comprises a plurality of diverters and furtherwherein said plurality of diverting rails are generally parallel to eachother.
 21. The method of claim 20 including diverting an article bydiverting a plurality of said pusher shoes to said plurality ofdiverting rails with said plurality of diverters.
 22. The method ofclaim 20 including laterally displacing an article without substantialrotation of that article.
 23. The method of claim 20 including laterallydisplacing an article with an initial rotation of that article.
 24. Themethod of claim 17 including providing a branch conveyor extendinglaterally at an angle to said conveying surface, wherein said secondlateral rate causing the article to align with said branch conveyor. 25.The method of claim 17 including laterally displacing an article withoutsubstantial rotation of that article.
 26. The method of claim 17including laterally displacing an article with at least a partialinitial rotation of that article.
 27. The method of claim 17 includingproviding a gradual transition between said first lateral rate and saidsecond lateral rate.
 28. The method of claim 17 wherein said at leastone diverting rail is at least partially curved.
 29. The sorter of claim17 including providing a gradual junction between said first portion andsaid second portion.